Halogenated hydrocarbons are widely used due to their inertness, low toxicity, and cleanliness. Thus, the chlorofluorocarbons are used as working fluids in air-conditioning systems used in automobiles, aircraft, and ships, in refrigerant systems used in trucks, water coolers, and commercial chillers, in industrial air conditioners, and the like. See, for example, a report by T. D. McCarson, Jr. et al. entitled "Halocarbon Recovery, Recycling, and Reclamation: Issues, Equipment, and Services" (published by the New Mexico Engineering Research Institute of Albuquerque, N. Mex. as report ESL-TR-90-30 in May of 1990, and available from the National Technical Information Service, 5285 Port Royal Road, Springfield, Va.).
It is widely believed that the halogenated hydrocarbons deplete the ozone layer surrounding the earth and thus allow the transmission of harmful radiation to the surface of the earth. Thus, thus use of halogenated hydrocarbons has been severely restricted by many major industrial countries.
In 1987, approximately 41 countries signed the "MONTREAL PROTOCOL ON SUBSTANCES THAT DEPLETE THE OZONE LAYER;" as of now, at least 62 countries have ratified such protocol. Some of the countries which are parties to this protocol include the United States, Canada, Australia, the United Kingdom, Japan, France, and Germany.
In order to encourage the recycling of halogenated hydrocarbon refrigerant, the United States Congress has enacted an excise tax on such ozone-depleting chemicals. However, recycled ozone-depleting chemicals are exempt from this tax. An example of how onerous this tax may be is presented in the December 1989 issue of "CFC Alliance: Special Bulletin" (CFC Alliance, 2011 Eye Street, N.W., Fifth Floor, Washington, D.C. 20006). On page 4 of this bulletin, an example is given of a "floor stocks tax." In this example, reference is made to an "XYZ" Company which ". . . holds 500 pounds of halon 2402 on Jan. 1, 1994. XYZ Company purchased the chemical in 1992. The floor stocks tax will equal $7,825."
Many of the States in the United States have also encouraged the recycling of halogenated hydrocarbon refrigerant by enacting strict laws governing the use of and recovery of halogenated hydrocarbons. The aim of many of these laws was to mandate the removal of halogenated hydrocarbon from refrigerant and air-conditioning systems.
However, much of the used refrigerant recovered from refrigeration systems contains impurities such as oil, acids, sludge, non-condensable materials, moisture, and the like. This impure refrigerant is not suitable for use in other refrigeration systems.
Means are available for recycling impure, recovered refrigerant. This recycling means generally comprise refrigeration filter--driers, and they generally are effective in removing up to about 90 percent of the impurities present in the recovered refrigerant. The effectiveness of such filter-driers depends upon how many times the refrigerant is cycled through the system. However, these purification means will not produce a recycled product which is substantially as pure as virgin refrigerant.
Means are also available for reclaiming impure, recovered refrigerant. These reclaiming means generally comprise a distillation apparatus. The distillation apparatus only can be used with recovered refrigerant of a specified purity.
By way of illustration, the "DuPont Refrigerant Reclamation Program" is described in document H-24085, which was published in February, 1990 by the FREON Products Division of DuPont Company (Customer Service Center, B-15305, Wilmington, Del. 19898). On page 2 of this document, it is specified that the R-11 refrigerant used in this program must be at least 99.8 weight percent pure, contain less than 1,000 parts per million of material boiling higher than the used refrigerant, contain less than 1,000 parts per million of material boiling lower than the used refrigerant, contain less than 100 parts per million of water, have a pH of at least 3.8, and contain less than 30 volume percent of oil.
By way of further illustration, the Genetron refrigerant reclamation program is described in a publication entitled "Renewing Resources To Meet The Fluorocarbon Challenge" which was published as bulletin 525-638 by the GENETRON Products Division of Allied-Signal Inc. (Post Office Box 1139R, Morristown, N.J.). In this publication it is specified that the recovered R-12 refrigerant, to be acceptable for the process, must be at least about 99.5 weight percent pure, contain less than 80 parts per million of water, have a pH of at least 3.5, and contain less than 30 volume percent of oil.
In addition to not being suitable for all recovered refrigerant, the use of the distillation apparatuses requires substantial expenditures of energy. Relatively high temperatures, high pressures, and large batches of material must be used. The use of these high temperatures and pressures increases the risk of venting refrigerant material to the atmosphere.
It is an object of this invention to provide an apparatus for reclaiming recovered refrigerant which is capable of producing refrigerant which is substantially as pure as new, virgin refrigerant.
It is another object of this invention to provide an apparatus for reclaiming recovered refrigerant which may be used with substantially any impure recovered refrigerant, regardless of the extent of the impurity or the chemical composition of the refrigerant.
It is another object of this invention to provide an apparatus for reclaiming recovered refrigerant which may be used at a temperature lower than ambient.
It is another object of this invention to provide an apparatus for reclaiming recovered refrigerant whose operation does not present a substantial risk of venting refrigerant vapor to the atmosphere.